People often make a note of something in order to remember to do it when they get home. Or, when they're at home, they often make lists of things to do when they get to the office. However, they oftentimes forget to look at that note when they get there.
Reminders like these comprise part of a user's to do list. They're different from other to do items because each of these has a location associated with it, and because the user would like to be reminded about them when they get to that location. Users today have a number of strategies for dealing with this problem: they make lists on paper, but sometimes forget to look at the lists; they leave messages on answering machines, but voice messages lack the permanence of paper-based messages and often get forgotten; they ask others to remind them, but the other people sometimes forget as well. Thus, a need exists for better location-based reminding and intelligence.
Many of today's location-based applications rely on the Global Positioning System (GPS) to determine their physical location. GPS determines the user's position by triangulating signals transmitted by a set of satellites constantly orbiting the earth. While GPS works extremely well on a large scale, it has a few problems:
GPS effectively requires line-of-sight visibility between the GPS antenna and the satellite network, which can be difficult when walking or driving, or when located between tall buildings. PA1 The GPS antenna is bulky. PA1 GPS doesn't work as well inside buildings, because of the line-of-sight visibility requirement. PA1 Civilian GPS is only accurate to hundreds of feet. (Military GPS is much more accurate.) PA1 GPS is still relatively expensive. PA1 Active badges require a significant infrastructure before they can work. Active badges transmit their locations using an infrared (IR) link. IR receivers located on the ceiling of each office see the active badge's identification transmission, and update a central server with the person's location, which in turn can reroute telephone numbers, etc. Without the receivers in every room, active badges are much less effective. PA1 Active badges only work in the office complex where the central server infrastructure has been created. PA1 Active badges create privacy concerns, because the central server is aware of the person's location. PA1 Active badges need to be worn externally so that line-of-sight connections can be made with the ceiling-mounted IR receivers. PA1 Only the network and the central server know about the person's location. A computer the person is carrying is unaware of the person's location, so cannot adapt itself based on that location. PA1 There is no networking or server infrastructure required. Each user builds their own infrastructure by placing beacons in key locations, and is also free to leverage beacons placed by others. PA1 Privacy issues are negated. Only your computer knows where you are-nobody else does. And your computer only knows where you are if you take it with you. PA1 The technology is designed to work indoors. PA1 The technology has no line-of-sight restrictions, so it can work even when the host computer has been put away and is contained inside something else. PA1 The technology is compact. PA1 The technology is inexpensive.
Various research institutes have investigated using location awareness to make people's computing environments adapt. A widely publicized experiment was Rank Xerox EuroPARC's use of Olivetti's Active Badges. At EuroPARC, telephones ring where you are, rather than ringing in your office when you're not there. In addition, you can locate people via these Active Badges. There are, however, some problems with the EuroPARC/Olivetti approach:
AppleLocator technology, the present invention approach, does not attempt to replace these prior technologies or to address all of the problems that they try to solve. Rather, it relies on simple, low-cost technology to provide a basic level of location awareness, which can be leveraged by both embedded and application software in the computer electronics that the user is carrying. In particular:
Further, a key observation which underlies the AppleLocator technology is that for many things in people's lives, knowing about only a few locations is still a significant advance. For instance, rather than knowing that you're within two blocks of a grocery store and you need to buy something, it probably suffices to know that you're on the way home, and be told that there were things that you needed to buy at the store.